Sample monitoring and flow control systems and methods are disclosed for monitoring of airborne particulates. A system may include a particle collection filter. The system also includes a fluid moving device for moving a sample through the particle collection filter. Further, the system includes a light source configured to direct irradiating light towards the particle collection filter. The system also includes a light detector positioned to receive the irradiating light passing through the particle collection filter and configured to generate a signal representative of an amount of the received light. Further, the system includes a controller configured to receive the signal and to control the fluid moving device based on the amount of the received light.